1. Field of the Invention
The invention herein relates to embroidery machinery. More particularly it relates to embroidery hoops used to hold individual workpieces while the workpieces are embroidered by the machines.
2. Description of the Prior Art
Embroidery has long been used to form decorative designs on fabrics by hand, and for commercial products, by machine. There are many commercial products made using embroidery machines, including garments, bed and bath linens, and decorative objects for home and office. One common product to which decorative embroidery is applied by machines is the baseball cap. Embroidery machines are used to apply team names and logos, as well as company names and logos, decorative names or initials, pictures of plants or animals, and many other designs.
Most embroidered products are assembled from several individual pieces of fabric. Before assembly, each piece of fabric which is to display an embroidered design, logo, etc. as part of the final product is inserted into a machine embroidery hoop and secured into the hoop. The hoop is then placed in a carrier which in turn is inserted into the embroidery machine in a position aligned with the embroidery needle, and the machine then applies the desired embroidered design, logo, etc. to the fabric in the normal manner. Once the embroidered design, logo, etc. is completed, the carrier is ejected from the machine. The operator then removes the hoop and separates the embroidered piece of fabric, which is then put with the other pieces of fabric to be assembled into the desired final product, such as a baseball cap. The hoop is then ready to receive a new unembroidered piece of fabric for the cycle to be repeated.
In the past it has been difficult to ensure correct alignment of the fabric workpiece in the hoop so that in the machine the embroidery can be properly applied. As a typical example, we can consider a baseball cap to which a team initial (such as the letter "O" in FIG. 1) is to be applied. For such a cap the workpiece is usually a triangular or rectangular piece of fabric which will ultimately be assembled as the front panel of the cap. It is common in the embroidery business for the workpiece to be secured into the hoop by use of adhesive tape. However, using adhesive tape causes numerous problems. Applying and subsequently removing the tape from the workpiece can damage the fabric; the tape often does not hold securely allowing the workpiece to shift position under the embroidery needle, so the embroidery becomes applied in the wrong location or the embroidery pattern becomes distorted; or pieces of the tape loosen and become stuck in the needles and inside the embroidery machine, so that the machine must be shut down to remove the tape. In addition, one must consider the cost of spoiled material and the operator's time spent changing, aligning and repositioning the tape for each new cycle, as well as the operator's time wasted in clearing the machine of displaced tape.
Numerous modifications have been made to machine embroidery hoops in an attempt to secure the workpieces better within the hoops, to avoid damage to the workpieces which come loose inside the machines, The possible modifications have been restricted, however, because the space within the machine to receive the hoop and carrier is very limited, especially as to height; in most machines the space for the hoop and carrier is only about 1" (25 mm) high. Prior inventors have produced a number of different devices which are disclosed in the prior art, but none of these has proved to be fully satisfactory. Typical examples of prior hoops are shown in U.S. Pat. Nos. 4,598,488 and 4,831,753 (both to R. N. Inteso). The Inteso hoops use toothed and clawed members as the elements for securing the workpiece. In order to work, such toothed or clawed members must necessarily dig into the workpiece fabric, thus marring the fabric and, if the fabric shifts during the operating cycle, possibly tearing the fabric. Use of the Inteso hoops also requires that machines be stopped fully for each hoop change, since the height of the Inteso hoops does not permit the repetitive reciprocating movement required without stopping the machine. This of course adds substantially to the length of each cycle and reduces the number of products which can be produced per unit of time.
It would therefore be very desirable to have a hoop structure which would hold a fabric workpiece securely so that it could be properly embroidered by the machine, but would hold the workpiece in a manner which would avoid any possible damage to the fabric and would allow free reciprocating movement without stopping the machine.